1. Field of the Invention
The present invention relates to a label printing and applying device, preferably of a portable type, referred to hereafter as a hand labeler, and more particularly to a printing pressure damping mechanism for use with the hand labeler, by which the squeezed force applied to the hand lever is damped to a preset level so as to maintain the printing pressure applied by the printing head at a constant level.
2. Description of the Prior Art
When the operating or hand lever of a hand labeler is squeezed, the yoke which is part of the hand lever is turned so that the printing head, which is carried by the yoke, is brought into abutment engagement with the platen which is fixed to the body of the hand labeler. This abutment prints the labels on the platen with desired indicia. Because the yoke of the hand labeler is turned by a manual operation, the printing pressure of each printing stroke by each operator would be different. In such a hand labeler, the platen is usually fixed to the body of the labeler. The type surface of the printing head is brought into abutment contact with the platen with a strong force. When the type surface to be printed is made of a rigid material, such as metal, the resultant strong printing force cannot be damped by the fixed platen and the printing head is vibrated with a small amplitude in the direction to and from the platen resulting in double printing on the labels.
On the other hand, if the type surface of the printing head is made of an elastic material, such as rubber, during the printing, the types are crushed on the platen, causing the imprints on the labels to be unclear.
Further, a rigid material type surface, may scratch or damage the label surfaces or the type surface and/or the surface of the platen may become worn or damaged due to the strong printing force.
Moreover, the rebound caused when the printing head hits the platen is transmitted to the hand of the user directly through the hand lever with the resultant disadvantages that the user has an uncomfortable feeling and that the squeezing operation cannot be carried out smoothly.